For now, these “new” smartcards are used only in dual mode, i.e. only two of the communication interfaces are used and are always active. One fundamental assumption is that such objects won't be put in an unknown environment: for instance a card that is used in ISO/MMC mode is not supposed to be put in a USB reader.
Some constraints are set between the interfaces to correctly boot the card. In that configuration, the boot sequence simply has to rely on the detection mechanism of one of these interfaces to correctly determine the running interface(s).
A problem is that interface detection is not 100% reliable. Some interface may be not detected and some other can be detected even if they are not present. This is due to the several possibility of implementation of interfaces into the reader, which are not standardized.
The power supply pin is shared between all interfaces and the card has no way to know which interface is the source of power. A goal is to have a portable object that can activate all the supported interfaces (here, ISO/MMC/USB/SWP). Some interfaces may be multiplexed on the same pins and may not be activated simultaneously.